1. Field of the Invention
The invention relates to a locking and disfiguring mechanism for an iontophoretic system including a patch and a controller.
2. Description of Related Art
Iontophoresis is the migration of ions when an electrical current is passed through a solution containing an ionized species, usually the ionic form of a drug or other therapeutic agent (hereinafter referred to as the "drug"). One particularly advantageous application of iontophoresis is the noninvasive transdermal delivery of ionized drugs into a patient. Iontophoretic drug delivery offers an alternative and effective method of drug delivery over other methods such as passive transdermal patches, needle injection, and oral ingestion, and is an especially effective method for children, the bedridden and the elderly.
Drug delivery via iontophoresis is done by applying current to electrodes of an iontophoretic patch. The current is usually supplied from a controller connected to the patch. The electrodes are respectively arranged within a drug reservoir, containing the drug ions, and a return reservoir, containing an electrolyte. When the patch is placed on the skin of a patient and the controller is turned on, the current applied to the electrodes forces the drug ions contained in the drug reservoir through the patient's skin and into the patient's bloodstream.
The controller usually contains an energy source, for example, a battery, as well as electrical circuitry for generating and regulating the current applied to the patch electrodes. Preferably, the controller is to be reused until its battery dies, while the patch is to be used only once to deliver a full drug dosage and then disposed.
The controller and patch may be connected together via an interconnection tab integral to the patch. This connection is (1) electrical--electrical interconnect leads and terminals connect the electrodes to the current regulating circuitry; and (2) mechanical--the tab is physically engaged in the controller housing. A problem in this connection may arise, however, if the interconnection tab can be easily removed from the controller housing during operation of the system. This will cause the patch to separate, either wholly or partially, from the controller, which in turn causes the patch to disconnect electrically from the controller. Without an electrical connection, drug delivery to the patient will cease, and the patient will receive only a partial drug dosage.
Another problem that may arise is the reuse, by the patient or health care provider, of a partially-used or spent patch. This reuse may be accidental or may be purposeful, but should be avoided. Not only is reusing a patch unsanitary, but will most likely result in the delivery of only a partial drug dosage.